Horton

Re: WIP: Faster Expression Processing v4

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, pgsql-hackers@postgresql.org
Date: 2017-03-23T17:40:04Z
Lists: pgsql-hackers 
Hi,

On 2017-03-23 13:14:59 -0400, Tom Lane wrote:
> Looking at some of the coding choices you made here, I see that you're
> making a hard assumption that called functions never scribble on their
> fcinfo->arg/argnull arrays.  I do not believe that we've ever had such
> an assumption before.

I think we did that before, e.g. ExecEvalScalarArrayOp(). Think there's
others too.


> Are we comfortable with that?  If so, we'd better document it.

I think it's ok, but we indeed should document it. I recall a note
somewhere... Can't find it anywhere however, might have misremembered a
note about pass-by-ref arguments.  fmgr/README? A note in
FunctionCallInfoData's definition?

Greetings,

Andres Freund

Commits

  1. Improve performance of ExecEvalWholeRowVar.

  2. Remove unreachable code in expression evaluation.

  3. Faster expression evaluation and targetlist projection.

  4. Avoid syntax error on platforms that have neither LOCALE_T nor ICU.

  5. Add configure test to see if the C compiler has gcc-style computed gotos.

  6. Improve regression test coverage for TID scanning.

  7. Improve expression evaluation test coverage.

  8. Fix two errors with nested CASE/WHEN constructs.